Edward toungman harbison



' (No Mom.) s sneets-sheet 1.

E. Y. HARRISON.

GRAB 0R GLAM SHELL DRBDGER.

Patented Mar. 18, 1890 a sheets-sheet 2 (No Model.)

E. Y. HARRISON. GRAB 0R GLAM SHELL DRBDGBR. 4

No. 423,427. Patented Mar. 18, 1890.

N. PETERS. Phnlo-Lilhgrlpher. Wahingk'm, D, C.

(No Model.) A 3 Sheets-Sheet 3. E. Y. HARRISON. GRAB 0R GLAM SHELL DREDGBR.

Patented Mar. 18, 1890.

UNITED STATES PATENT OFFICE.

EDXVARD YOUNGMAN HARRISON, OF BALLINA, RIOHMON D RIVER,

' NEV SOUTH VALES.

GRABv OR CLAM-SHELL DREDGER.l

lSl?ECIEICA'LION forming part Of Letters Patent No. 423,427, dated March 18, 1890. Application filed July 22, 1889. Serial No. 318,340. (No model.)

To all whom` t may concern.-

Be it known that I, EDWARD YOUNGMAN HARRISON, master and engineer of the steamdredger Zeta, a subject of the Queen of Great Britain, residing at Ballina, Richmond River, in the British Colony of New South Vales, have invented new and useful Improvements in Grab or Clam-Shell Dredger- Buckets, of which the following is a specification.

This invention has referenceto improve- Inents in grab or clam-shell dredger-buckets,

whether for lifting silt or mud, or of open construction for lifting stone .and ballast, such buckets having two jaws and being worked by chains arranged to control the closing and opening of such jaws. It has been specially devised in order that, compared with the buckets heretofore constructed, the complication in working the closing and opening chains Inay be considerably reduced, that they may be manufactured of comparatively lighter material and yet retain as great strength, and that they Inay be used with greater' success in obtaining their load, and that they may be more simple in Inake and in use.

These improvements in grab or clam-shell dredger-buckets will now be described in detail by reference to the drawings, in which-' Figure l is a plan of a grab dredgenbucket constructed according to my invention; and Fig. 2 is a side elevation of same, (both with chains unattached.) Fig. 3 is a sectional elevation, and Fig. 4 is an end elevation, of the same, with the jaws opened and the closing and hauling chain slack. Figs. 5 and 6 are respectively a side and end view in elevation of a modified form of grab dredger-bucket.

A and B are the jaws; C, hinge-shaft; D, hauling and closing chain; E, opening-chain.

A B are central partitions; A2 B2, diagonal stays.

A3 BB are lugs or eyes.

A4 B4 are strengthening pieces or bars.

A5 B5 are bottom teeth.

C are hingeplates or straps; D", strengthning-piece on partition A 5 D2, shackle; D3,

ase or jaws fixed to partition B; D4, sheave llleyon pin D5 in jaws D3; D0 and D7,

hinge plates or straps fixed, respectively, to partitions A and B and taking over shaft C.

D8 is a sheave or pulley. E are slings; E2, junction-shackle. l In operation the grab dredger-bucket is slung and lowered in the position shown in j Fig. 4. When chain E tightens, slings E keep the jaws A and B fully distended. To fill the bucket, the opening-chain E is slackened and the hauling and closing chain D is wound up, when it, pulling around sheave D8 and sheave D4, will close the jaws A and B, and when they have closed over a load will raise such load to where required,'and when it is slackened, chain E being tight, the jaws A and B will open and discharge the contents of the bucket.

In the modified forni of my invention a,

stone and ballast lifter, instead of a silt or mud lifter, is shown. A andB are prongs or jaws; C, hinge-shaft; D, hauling and closing chain; E, openingchain. AB BB are lugs or eyes. A X (dotted) show Where joints in prongs A and B Inight be placed. C are lugs on hinge C. D are slings; D2, junctionshackle; E', slings; Erack-plate; E3, slings; E4, j unct-ion-shackle. operations to those described will have like effect-that is, by hauling on chain E the jaws or prongs A and B will open and become distended, and by hauling on chain D the jaws or prongs will grasp and lift a load.

Although I have shown the preferable construction of bucket for their respective uses, it is to be understood that I might dispense with the use of sheaves or pulleys for guiding the hauling and closing chain, as explained in the first-described bucket, and attach such chain to brackets on the hinge-shaft, as eX- plained in last-described bucket; and it is also to be understood that I do not confine myself to the precise mechanical means by which my invention Inay be carried out so long as the nature of the same be retained.

Having now particularly described and eX- In this bucket similar plained the nature 'of my said invention and 95 performed,

IGQ

attachment `for the hauling and closing chain, for each jaw, and the an gle-pieces and bottom and of jaws or casings for guiding sheaves or teeth thereon, substantially as set forth. pulleys, and of such guiding sheaves or pul- EDWARD YOUNGMAN HARRISON.

leys, vsubstantially as described. Witnesses:

2. In a grab dredger-bueket, the combina- FRED WALSH, tion, with the shaft and the jaws hinged there- F. M. Inst. P. A. to, of hinge-plates or straps secured to said THOS. J WARD, shaft and extending outward therefrom, one CZe'rc to Edwd. Waters, Sydney. 

